The incorporation of electronic devices with pneumatic tire and wheel structures yields many practical advantages. Tire electronics may include sensors and other components for relaying tire identification parameters and also for obtaining information regarding various physical parameters of a tire, such as temperature, pressure, tread wear, number of tire revolutions, vehicle speed, etc. Such performance information may become useful in tire monitoring and warning systems, and may even potentially be employed with feedback systems to regulate tire or vehicle parameters.
Yet another potential capability offered by electronics systems integrated with tire structures corresponds to asset tracking and performance characterization for commercial vehicular applications. Commercial truck fleets, aviation crafts and earthmover/mining vehicles are all viable industries that could utilize the benefits of tire electronic systems and related information transmission. Radio frequency identification devices (RFID) can be utilized to provide unique identification for a given tire, enabling tracking abilities for a tire. Tire sensors can determine the distance each tire in a vehicle has traveled and thus aid in maintenance planning for such commercial systems. Vehicle location and performance can be optimized for more expensive applications such as those concerning earth-mining equipment. Entire fleets of vehicles could be tracked using RF tag transmission, exemplary aspects of which are disclosed in U.S. Pat. No. 5,457,447 (Ghaem et al.).
U.S. Pat. No. 5,749,984 (Frey et al.) discloses a tire monitoring system and method that is capable of determining such information as tire deflection, tire speed, and number of tire revolutions. Another example of a tire electronics system can be found in U.S. Pat. No. 4,510,484 (Snyder), which concerns an abnormal tire condition warning system. U.S. Pat. No. 4,862,486 (Wing et al.) also relates to tire electronics, and more particularly discloses an exemplary revolution counter for use in conjunction with automotive and truck tires. Additional background information regarding RFID technology may be had by reference to co-pending, commonly owned U.S. patent application Ser. No. 10/697,576, filed Oct. 30, 2003, entitled “Acoustic Wave Device With Digital Data Transmission Functionality” incorporated herein for all purposes.
In conventional implementations of RFID devices in tire-related applications, such devices typically store collected and previously recorded information for delayed transmission. The stored collected data may relate to tire operating parameters such as tire pressure, tire temperature, speed, total number of revolutions, and other parameters as well as calculated data such as temperature at speed, miles at temperature, pressure variation over miles or time and other data of specific interest depending on exact usage of the RFID device. Previously recorded data may include such as a serial number or identification number for the tire with which a particular RFID device may be associated or other data such as manufacturing data including manufacturer and/or place, time and date of manufacture or other data related to the tire or RFID device per se.
Transmission of data from RFID devices may be initiated automatically or triggered manually. Manual triggering of a transmission from such an RFID device normally requires an operator to employ some form of interrogator device. Interrogator devices may be fixed or handheld devices that will typically be configured to transmit a radio frequency (RF) signal that is received by an RFID device that interprets the transmitted signal as an instruction to begin data transmission. One advantage of using an RF field-generating interrogator resides in the fact that the RF field itself may be used as a power source for the RFID device. Alternative methods for triggering data transmission are known and include such as placing a permanent magnet in proximity to a tire electronics package to operate a mechanical or electrical switch to begin data transmission or physically removing a tire from its wheel to gain access to an electrical connector associated with the tire electronics and thereby gain access to stored data.
It is sometimes the case that in radio frequency transmission systems, the specialized apparatus necessary to trigger data transmission may not be readily available when needed. Even relatively simple equipment like a permanent magnet might not be available, and other techniques for gaining access to stored data such as physically removing a tire may be impractical or impossible in the time frames that may be associated with normal vehicle movement. While various implementations of RFID devices in tire electronic systems have been developed, and while various combinations of information have been wireless relayed from tire or wheel assemblies using conventional technologies, no design has emerged that generally encompasses all of the desired characteristics as hereafter presented in accordance with the subject technology.
In accordance with the present subject matter, it is appreciated that certain advantages of piezoelectric materials have long been recognized. However, such technology is constantly improving, thus potentially affording applications that utilize piezoelectric materials with improved operating capabilities. Examples of relatively new advances in piezoelectric technology are provided in U.S. Pat. No. 5,869,189 (Hagood, IV et al.) and U.S. Pat. No. 6,048,622 (Hagood IV et al.), directed to composites for structural control. The presently disclosed technology concerns further advances in piezoelectric structure applications such that a piezoelectric power generating and sensing device can be integrated with a tire or wheel assembly for purposes of data transmission to associated RFID or other tire related data collection and storage devices. It should be appreciated, however, that although the principally discussed mechanism for data detection and transmission involves piezoelectric sensors, other types of mechanical vibration sensitive elements could also be employed. Thus the basic methodology illustrated involves the mechanical transmission of data through a tire or other housing or containment element. Moreover, the device or mechanism used for detecting the mechanical vibrations involved with such data transmission as well as the devices and methods used to produce such mechanical vibrations are secondary in nature to the basic principles disclosed.
Currently pending and co-owned U.S. patent application Ser. Nos. 10/143,535 and 10/345,040 disclose aspects of generating and harvesting electric power from a rotating tire's mechanical energy using piezoelectric materials. The present invention concerns further applications offered by the integration of such piezoelectric structures in a tire or wheel assembly. More particularly, such piezoelectric structures can be combined with additional features to provide an extremely simple and convenient methodology for manually or automatically initiating information transfer to an RFID or other device mounted in association with a tire or wheel assembly in accordance with aspects of the present invention.
The disclosures of all of the foregoing United States patents and patent applications are hereby fully incorporated into this application for all purposes by reference thereto. While various tire electronics systems have been developed, no design has emerged that generally encompasses all of the desired characteristics as hereafter presented in accordance with the subject technology.